P0123
DTC P0123: Throttle Position Sensor (main) Circuit High InputThrottle Position Sensor (Main) Circuit (Part 1):
Throttle Position Sensor (Main) Circuit (Part 2):
CIRCUIT OPERATION
- A 5-volt power supply is applied on the throttle position sensor (main) power terminal (terminal No. 5) from the ECM (terminal No. 12).
- A voltage that is according to the throttle opening angle is sent to the ECM (terminal No. 10) from the throttle position sensor (main) output terminal (terminal No. 4)
- The ground terminal (terminal No. 3) is grounded with ECM (terminal No. 13).
TECHNICAL DESCRIPTION
- The throttle position sensor (main) outputs voltage which corresponds to the throttle valve opening angle.
- The ECM checks whether the voltage is within a specified range.
DESCRIPTIONS OF MONITOR METHODS
Throttle position sensor (main) output voltage is out of specified range.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS(Other monitor and Sensor)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
DTC SET CONDITIONS
Logic Flow Chart
Logic Flow Chart:
Check Condition
- Ignition switch is "ON" position.
Judgement Criterion
- Throttle position sensor (main) output voltage should be 4.8 volts or more for 0.3 second.
FAIL-SAFE AND BACKUP FUNCTION
- Throttle opening degree is restricted.
- Throttle opening degree position is in default position if throttle position sensor (sub) fails.
OBD-II DRIVE CYCLE PATTERN
None.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Throttle position sensor failed.
- Open or shorted throttle position sensor (main) circuit, harness damage, or connector damage.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991910: Main Harness A
- MB991658: Test Harness
STEP 1. Using scan tool MB991958, check data list item 13: Throttle Position Sensor (main).
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Detach the intake air hose at the throttle body.
4. Disconnect the connector of the throttle position sensor.
5. Use test harness special tool (MB991658) to connect only terminals No. 3, No. 4, No. 5, and No. 6.
6. Set scan tool MB991958 to the data reading mode for item 13, Throttle Position Sensor (main).
- Output voltage should be between 0.3 and 0.7 volt when the throttle valve is fully closed with your finger.
- Output voltage should be 4.0 volts or more when the throttle valve is fully open with your finger.
7. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : It can be assumed that this malfunction is intermittent.
NO : Go to Step 2.
STEP 2. Check harness connector B-11 at throttle position sensor for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 3.
NO : Repair or replace it. Then go to Step 14.
STEP 3. Measure the sensor supply voltage at throttle position sensor harness side connector B-11.
1. Disconnect the connector B-11 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No. 5 and ground.
- Voltage should be between 4.9 and 5.1 volts.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the measured voltage between 4.9 and 5.1 volts?
YES : Go to Step 6.
NO : Go to Step 4.
STEP 4. Check harness connector B-09 at ECM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 5.
NO : Repair or replace it. Then go to Step 14.
STEP 5. Check for open circuit and short circuit to ground between throttle position sensor connector B-11 (terminal No. 5) and ECM connector B-09 (terminal No. 12).
Q: Is the harness wire in good condition?
YES : Go to Step 9.
NO : Repair it. Then go to Step 14.
STEP 6. Check the continuity at throttle position sensor harness side connector B-11.
1. Disconnect the connector B-11 and measure at the harness side.
2. Measure the continuity between terminal No. 3 and ground
- Continuity (2 ohms or less)
Q: Does continuity exist?
YES : Go to Step 10.
NO : Go to Step 7.
STEP 7. Check harness connector B-09 at ECM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 8.
NO : Repair or replace it. Then go to Step 14.
STEP 8. Check for open circuit and harness damage between throttle position sensor connector B-11 (terminal No. 3) and ECM connector B-09 (terminal No. 13).
Q: Is the harness wire in good condition?
YES : Go to Step 9.
NO : Repair it. Then go to Step 14.
STEP 9. Using scan tool MB991958, check data list item 13: Throttle Position Sensor (main).
1. Turn the ignition switch to the "ON" position.
2. Detach the intake air hose at the throttle body.
3. Disconnect the connector of the throttle position sensor.
4. Use test harness special tool (MB991658) to connect only terminals No. 3, No. 4, No. 5, and No. 6.
5. Set scan tool MB991958 to the data reading mode for item 13, Throttle Position Sensor (main).
- Output voltage should be between 0.3 and 0.7 volt when the throttle valve is fully closed with your finger.
- Output voltage should be 4.0 volts or more when the throttle valve is fully open with your finger.
6. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor operating properly?
YES : It can be assumed that this malfunction is intermittent.
NO : Replace the ECM. When the ECM is replaced, register the ID code. Then go to Step 14.
STEP 10. Check harness connector B-09 at ECM for damage.
Q: Is the harness connector in good condition?
YES : Go to Step 11.
NO : Repair or replace it. Then go to Step 14.
STEP 11. Check for harness damage between throttle position sensor connector B-11 (terminal No. 5) and ECM connector B-09 (terminal No. 12).
Q: Is the harness wire in good condition?
YES : Go to Step 12.
NO : Repair it. Then go to Step 14.
STEP 12. Check for open circuit, short circuit to ground and harness damage between throttle position sensor connector B-11 (terminal No. 4) and ECM connector B-09 (terminal No. 10).
Q: Is the harness wire in good condition?
YES : Go to Step 13.
NO : Repair it. Then go to Step 14.
STEP 13. Replace the throttle body assembly.
1. Replace the throttle body assembly.
2. Turn the ignition switch to the "ON" position.
3. After the DTC has been deleted, read the DTC again.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P0123 set?
YES : Replace the ECM. When the ECM is replaced, register the ID code. Then go to Step 14.
NO : The inspection is complete.
STEP 14. Using scan tool MB991958, read the diagnostic trouble code (DTC).
1. Turn the ignition switch to the "ON" position.
2. After the DTC has been deleted, read the DTC again.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is DTC P0123 set?
YES : Retry the troubleshooting.
NO : The inspection is complete.